Copper components are widely used in many modern electronic devices and other manufactured goods. Copper has the second highest electrical conductivity among the elements and is also a good thermal conductor. The metal is easily worked and readily available. However, one drawback to copper in some uses is that it reacts with oxygen in the air to form a layer of copper oxide.
A similar problem is encountered with some other metals used in electronic devices, but most of these other metals can be protected from corrosion at air bearing surfaces with a thin film of diamond like carbon (DLC). Such films on bare copper have been found to be inadequate to protect the surface over the long term. Corrosion rates of DLC films on copper substrates have been found to be 1 to 2 orders of magnitude worse (higher) than those on NiFe substrates or similar substrates.
This problem results in a corrosion risk for copper surfaces exposed to oxygen. In disc drives, for example, Air Bearing Surfaces (ABS) of recording head transducer designs may have exposed copper surfaces that are at risk for corrosion. If a recording head transducer becomes corroded, the surface will become covered with copper oxide, and the DLC film may delaminate. In addition, in many electronic devices the physical clearances are very small, and corrosion may interfere with the device physically, as well as magnetically and electronically.